fix: allow lexical import shadowing

cmd/wcc/ww.h

@@ -606,10 +606,8 @@ struct Checker {
 					 * rather than colliding io.read. */
 	int	cur_source;	/* lexical source-file scope of the declaration
 				 * currently being checked. */
-	Node	*file;	/* current N_FILE root; used by check_module_shadow
-			 * to consult the declaring source file's own `use`
-			 * directives when refusing param/let names that
-			 * would shadow an imported module bareword. */
+	Node	*file;	/* current N_FILE root; owns source-local import
+			 * qualifier lookup and usage accounting. */
 	int	loops;	/* nesting count for break/continue */
 	int	matcharms;	/* nesting count for yield */
 	int	errs;